Disintegrators



7 June 29, 1965 Filed July 30,

D. J. DRINKWATER 3,191,875

DISINTEGRATORS 1963 I5 Sheets-Sheet 1 Donald J. Drinkwoter ATTORNEY United States Patent 3,191,875 DISINTEGRATORS Donald J. Drmkwater, Denver, Colo., assignor to Mine and Smelter Supply Company, Denver, Colo., a corporation of Colorado Filed July 30, 1963, Ser. No. 298,710 14 Claims. (Cl. 241-183) This invention relates to improvements in disintegrators of the kind known as rod or ball mills adapted to reduce hard substances such as cement, clinkers, rock, ore, coal or the like to relatively small particles or to pulverize the same.

Heretofore, it has been the practice to reduce such material in a revolvable metallic cylindrically shaped shell or drum containing a plurality of comparatively large and heavy metal balls or rods which are intermittently lifted as the drum rotates and dropped on the material to be crushed in the lower part of the drum. However, in recent years it has been found that the balls or rods can be dispensed with and the crnshable material itself used as the grinding media, i.e., chunks of such material could be lifted as the drum rotates and dropped on the material remaining in the lower part of the drum and thereby perform the same function as the metallic rods or balls. This method of grinding is called autogenous grinding. But whatever media are used to effect the grinding or pulverization in mills of the kind contemplated herein, some means must be provided to assist in lifting the grinding media. Otherwise, the crnshable material would simply slide down the inner side of the drum as it rotates. One such means, and one commonly employed, is the utilization of longitudinally extending lift or wear bars positioned radially on the inside of the shell and bolted or otherwise secured thereto. These bars aid in carrying the grinding media up with the ascending side of the drum as the latter rotates about its longitudinal axis.

In operation, rod or ball mills gradually lose elliciency because the lifter bars wear down in height which results in a progressive loss of lift. By lift is meant the distance measured radially between the tops of the bars and the inner surface of the shell or, if the shell is equipped with liner plates (as is usually the case), between the top surfaces of the barsand the liner plates. When the bars are worn away to such an extent as to provide little or no lift, grinding virtually ceases. Thereupon it becomes necessary to shut down the mill, remove the worn lifters and replace them with new ones by working inside the mill. The rate of wear on the lifters, particularly in autogenous grinding, is very high, sometimes requiring replacements every two or three months depending on the time the mill is in operation and the kind of material being crushed. Because of the gradual wear on the bars and the lack of means for compensating for the same, the efficiency of the mill is unnecessarily impaired. Also, because of the manner of securing the bars in place and the procedures necessary to be employed for replacing them, the replacement of the bars not only consumes a great deal of time but also results in an excessive amount of scrap loss because of the fact that much of the material remaining in the drum must be discarded as well as the bars themselves. My invention overcomes these disadvantages by employing lift bars which may be adjusted in height to maintain their lift from without the shell and which may be removed and replaced either by entering or without entering the shell.

Another aspect of my invention relates to the employment of non-adjustable lift bars which may be installed from without the shell.

Additionally, another of my improvements contemplates a change in form of the shell or drum itself which lies outside the domain of mere construction and which results in the attainment of advantages heretofore unforeseen. In shape, drums or shells of grinding mills are usually circular in cross-section and are fabricated from steel plate rolled to the prescribed diameter, sometimes as much as twenty-five feet. As the diameters of the shells become larger, the rolling of the plates is attended with increasing difiiculty and, in so far as really large shells are concerned, they must be sectionalized to permit shipment to the mill sites and reinforced to provide the necessary rigidity.

I have found that the shells may be made of straight segments so that the resulting shells are polygonal in configuration rather than circular. This permits of the utilization of unprocessed flat plate sections which are considerably less expensive than sections requiring work to roll them to diameter and also lends itself to the use of less expensive liner plate designs and particularly to the use of adjustable lifter bars, all of which will hereinafter he described in more detail.

Accordingly, one object of my invention is to provide a drum for a grinding mill incorporating means whereby lift bars may be installed from without the drum;

Another object of my invention is to provide a drum for a grinding mill equipped with lifter bars which may be adjusted in height from without thedrum;

Another object of my invention is to provide a drum for a grinding mill incorporating adjustable lift bars;

Another object of my invention is to provide a drum for a grinding mill incorporating lift bars which can be readily replaced;

Another object of my invention is to provide a drum for a grinding mill equipped with means whereby lift bars may be installed from without the drum and adjusted in height from within the drum, and

Still another object of my invention is to provide a polygonal drum for a grinding mill.

These and other objects of my invention will become apparent as the description proceeds. Embodiments of the invention are illustrated by way of example in the accompanying drawings, wherein:

FIG. 1 is a cross-sectional view of a circular drum showing a means for adjusting a lift bar;

FIG. 2 is a longitudinal sectional view taken along the line 22 of FIG. 1, showing my adjustable lift bar in its lowermost position;

FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG. 2, showing through bolts and nuts for holding the bar in place and the housing for such bar;

FIG. 4 is a view similar to FIG. 3, showing set screws for vertically adjusting the bar;

FIG. 5 is a cross-sectional view showing the bar in a position adjusted higher than that shown by FIG. 2;

FIG. 6 is a longitudinal sectional view showing the bar adjusted to the position illustrated by FIG. 5;

FIG. 7 is an exploded view showing the relation of the bar to the drum and the adjustments therefor;

FIG. 8 is a fragmentary perspective view showing a non-adjustable bar within a drum and means for securing the same in place from without the drum;

FIG. 9 is a cross-sectional view of a two-piece lift bar;

FIG. 10 is a cross-sectional view of an alternative means for holding the bar in adjusted position;

FIG. 11 is a perspective view showing an adjustable lift bar applied to a polygonally shaped shell;

FIG. 12 is a longitudinal sectional view of a lift bar and showing an alternative means for adjusting the same;

FIG. 13 is a fragmentary side elevation of a section of the bar shown by FIG, 12, and

FIG. 14 is a cross-sectional view of the bar taken along the line 14-14 of FIG. 13.

In the following description similar reference characters designate corresponding parts in all of the views.

An important part of my invention pertains to the manner of or means for applying a lift or wear bar to the shell of a grinding mill regardless of its cross-sectional shape. The preferred means is illustrated by FIGS. 1 to 7, inclusive. Referring to such figures, it will be seen that a species of my invention has been applied to a mill having a conventional circular drum designated generally by the letter S, the drum being provided with a liner L. Such drum consists generally of a plurality elongated arcuately shaped sections 1 circumferentially spaced from each other. The liner for each drum section may be of any type or material. As shown, it consists of the same number of sections as the drum, and all such sections are secured together by any suitable means.

Manifestly, since the drum sections are spaced circumferentially from each other, some means must be provided for connecting them together. For this purpose I have provided a plurality of troughs open on their upper sides to form elongated pockets. These troughs are secured to the exterior surface of the drum and extend the full length of the same and span the spaces between the drum sections. Specifically, they consist of side portions 3, end portions 4 and removable bottom portions 5 attached to the bottom edges of the sides by cap bolts 6 or the like. The upper edges of the sides of each trough are secured to the exterior edge portions of adjoining drum sections by any suitable means, such as by welds 7. An elongated lift or wear bar 8 is removably positioned for vertical adjustment in each trough.

In the preferred embodiment of my invention, such bars, which may be either integral, as shown for example in FIG. 1, or sectional as shown by FIG. 9, are secured in place by any suitable means such as by through bolts 9 provided with block nuts 10. Vertical adjustment of the bars in this modification is accomplished by set screws 11 extending through the bottom of the troughs and contacting the under sides of the bars. It will be understood, however, that other conventional means for adjusting the height of an object, such as shims, may be employed.

Another specie of my invention is illustrated by FIGS. 12 to 14, inclusive. In this embodiment, the lift bars are beveled on their lower sides at the ends thereof to form cam surfaces and are secured in place by any suitable means, such as by through bolts as previously described. However, in this form of my invention vertical adjustment of the bars is accomplished by wedges 12 which are shiftable under the beveled ends of the bars by screw bolts 13 screwed through the ends 4 of the troughs. As shown, the lift bars and wedges are slidably connected together by tongue 14a and mortise 14 connections.

Still another specie of my invention is illustrated by FIG. 10. In this modification I contemplate drilling a series of vertically aligned holes 15 through the sides of the trough and the contained lift bar and insert a bolt 16 through aligned holes to secure the desired adjustment.

As previously intimated, I contemplate the replacement of non-adjustable lift bars in existing mills by cutting holes in the ends E of the shells and welding open end boxes 17 around the holes. By this means replacement bars may be inserted endwise from without the shells through the boxes and secured in place by bolts 18 extending through the boxes and ends of the bars. And for reasons hereinbefore stated, I propose to fabricate the drums or shells of fiat plate material so that the finished product will be polygonal in shape as illustrated by FIG. 11.

Having fully described my invention, what I desire to claim and secure by Letters Patent is:

1. In a disintegrator, a revolvable drum provided with an outer shell, elongated pockets extending lengthwise thereof, lift bars carried in said pockets, extending into the interior of the drum, and means associated with said drum for adjusting the lift of said bars relative to said shell.

2. The combination set forth in claim 1 wherein said bars are slidably carried in said pockets.

3. The combination set forth in claim 1 wherein said drum is provided with circumferentially spaced liner plates and the said pockets are provided by the spaces between said plates.

4. In a disintegrator, a revolvable drum provided with elongated pockets extending lengthwise thereof and lift bars carried in said pockets, said drum comprising longitudinally extending sections circumferentially spaced apart from each other and the said pockets being provided by troughs having open upper sides and wherein said troughs are secured to the exterior surface of said drum and span the spaces between said sections.

5. In a disintegrator, a revolvable drum provided with elongated pockets extending lengthwise thereof and lift bars carried in said pockets, said drum being provided with aligned openings in the ends thereof and open end boxes being secured to said ends around said openings wherebylift bars may be inserted through said boxes from without said drum.

6. The combination set forth in claim 4 wherein the bottom portions of said troughs are removable whereby lift bars may be inserted therein.

7. The combination set forth in claim 4 wherein an end portion of at least one of said troughs is removable whereby a lift bar may be inserted endwise therein.

8. The combination set forth in claim 4 wherein a lift bar is carried in at least one of said troughs and means are associated with the said trough for adjusting the bar vertically.

9. The combination set forth in claim 8 wherein means are associated with the trough for holding the bar in adjusted position.

10. The combination set forth in claim 9 wherein the means for holding the bar in adjusted position comprises bolts extending through aligned holes drilled throughthe sides of the trough and bar.

11. The combination set forth in claim 9 wherein the means for adjusting the bar vertically and holding the same in adjusted position comprises through bolts extending through the bar and the bottom of the trough in which the same is carried and set screws extending through the bottom of the trough and contacting the bar.

12. The combinaion set forth in claim 9 wherein the means for adjusting the bar vertically and holding the same in adjusted position comprises through bolts extending through the bar and the bottom of the trough and wedges under the ends of the bar.

13. In a disintegrator, a revolvable outer shell polygonal in cross section and fabricated of fiat plate sections, the said sections being spaced apart from each other, a plurality of spaced elongated troughs forming pockets having open upper sides secured to said shell and spanning the spaces between said sections, and lift bars carried in said pockets.

14. In a distintegrator, a revolvable drum provided with an outer shell, spaced longitudinally disposed lift bars projecting into the interior of said shell, liner sections disposed between the lift bars, and means associated with the drum for adjusting the lift of said bars.

References Cited by the Examiner UNITED STATES PATENTS 2,275,992 3/42 Rahner 241-183 2,611,546 9/52 Posselt 241-183 3,138,338 6/64 McKenna 241-300 X ANDREW R. JUHASZ, Primary Examiner. 

1. IN A DISINTEGRATOR, A REVOLVABLE DRUM PROVIDED WITH AN OUTER SHELL, ELONGATED POCKETS EXTENDING LENGTHWISE THEREOF, LIFT BARS CARRIED IN SAID POCKETS, EXTENDING INTO THE 